package com.ufaud.ais.pub.dao.hibernate;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.ufaud.ais.pub.dao.IGenericCRUDDao;

/**
 * This class serves as the Base class for all other DAOs - namely to hold
 * common CRUD methods that they might all use. You should only need to extend
 * this class when your require custom CRUD logic.
 * 
 * <p>
 * To register this class in your Spring context file, use the following XML.
 * 
 * <pre>
 *      &lt;bean id="fooDao" class="org.foj.dao.hibernate.GenericDaoHibernate"&gt;
 *          &lt;constructor-arg value="org.foj.model.Foo"/&gt;
 *          &lt;property name="sessionFactory" ref="sessionFactory"/&gt;
 *      &lt;/bean&gt;
 * </pre>
 * 
 * @author <a href="mailto:bwnoll@gmail.com">Bryan Noll</a>
 * @param <T>
 *            a type variable
 * @param <PK>
 *            the primary key for that type
 */
public class GenericCRUDDaoHibernate<T, PK extends Serializable> extends
		HibernateDaoSupport implements IGenericCRUDDao<T, PK> {
	/**
	 * Log variable for all child classes. Uses LogFactory.getLog(getClass())
	 * from Commons Logging
	 */
	protected final Log log = LogFactory.getLog(getClass());
	private Class<T> persistentClass;

	/**
	 * Constructor that takes in a class to see which type of entity to persist
	 * 
	 * @param persistentClass
	 *            the class type you'd like to persist
	 */
	public GenericCRUDDaoHibernate(final Class<T> persistentClass) {
		this.persistentClass = persistentClass;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public List<T> getAll() {
		return super.getHibernateTemplate().loadAll(this.persistentClass);
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public List<T> getAllDistinct() {
		Collection result = new LinkedHashSet(getAll());
		return new ArrayList(result);
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public T get(PK id) {
		T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
				id);

		if (entity == null) {
			log.warn("Uh oh, '" + this.persistentClass + "' object with id '"
					+ id + "' not found...");
			throw new ObjectRetrievalFailureException(this.persistentClass, id);
		}

		return entity;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public boolean exists(PK id) {
		T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
				id);
		return entity != null;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public PK save(T object) {
		return (PK) super.getHibernateTemplate().save(object);
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public T merge(T object) {
		return (T) super.getHibernateTemplate().merge(object);
	}

	/**
	 * {@inheritDoc}
	 */
	public void remove(PK id) {
		super.getHibernateTemplate().delete(this.get(id));
	}
	
	/**
	 * {@inheritDoc}
	 */
	public void evict(T object) {
		super.getHibernateTemplate().evict(object);
	}

	@SuppressWarnings("unchecked")
	public List<T> findByNamedQuery(String queryName, Map<String, Object> paramMap) {
		// 1.准备查询参数
		String[] paramNames = new String[paramMap.size()];
		Object[] paramValues = new Object[paramMap.size()];
		int index = 0;
		Iterator<String> i = paramMap.keySet().iterator();
		while (i.hasNext()) {
			String key = i.next();
			paramNames[index] = key;
			paramValues[index++] = paramMap.get(key);
		}
		// 2.执行查询并返回结果
		return getHibernateTemplate().findByNamedQueryAndNamedParam(queryName, paramNames, paramValues);
	}

}
